In manufacturing processes of a semiconductor device, in which a stacked structure of an integrated circuit is formed on the surface of a substrate, such as for example, a semiconductor wafer (hereinafter, referred to as a “wafer”), there is known a single wafer liquid processing apparatus for removing, for example, dusts and native oxides by supplying an alkaline or acidic chemical liquid to the front surface (top surface) or the rear surface (bottom surface) of a rotating wafer.
As an example of such a liquid processing apparatus, there is an apparatus including an annular guide (hereinafter, referred to as a “guide ring”) provided in the circumference of a wafer in such a manner that the guide leads to the height positions of front and rear surfaces of the wafer. See, e.g., Japanese Patent Application Laid-Open No. 2011-108732: paragraphs [0031] to [0032], and FIG. 4. The guide ring is rotated together with the wafer so that the processing liquid scattered from the front surface (the top surface) of the wafer is guided to the outside through the top surface of the guide ring, and also the processing liquid scattered from the rear surface (the bottom surface) of the wafer is guided to the outside through the bottom surface of the guide ring. As the processing liquid is guided to the outside of the wafer by the guide ring in this manner, the processing liquid may be suppressed from forming mists by being entrained to turbulent flow formed around the rotating wafer, and, after the liquid processing, the mists adhered to the wafer may be reduced.
However, on the peripheral edge of the wafer, an area chamfered to be slanted, called a bevel, is formed. In some cases, a processing liquid discharged along the bevel may not flow along the guide ring. Also, when flexure occurs in a wafer due to the large size of the wafer, the scattering direction of the processing liquid may be considerably changed. Thus, in some cases, the processing liquid may not flow along the guide ring. When the processing liquid does not flow along the guide ring, the processing liquid may collide with, for example, a liquid drain cup provided in the outside of the guide ring, thereby producing mists. Further, there is a possibility that the formed mists cannot be guided to the outside of the wafer, and thus may be a cause of polluting the wafer.